This study was conducted to isolate, identify, and test the efficiency of some fungi in the decomposition of calcium from cement-contaminated soil around the area of El-Mergib Cement Factory, Al-Khums, Libya. Soil samples were collected from three different spots (inside the factory wall, 150 meters, and 300 meters away from the factory) with four replicates for each spot. Control samples from uncontaminated soil were also collected and replicated to compare the results. Twelve species from four fungal genera (Rhizopus, Penicillium, Fusarium, and Aspergillus) were isolated and identified utilizing Sabouraud Dextrose Agar (SDA) medium. The decomposition efficiency of calcium from the contaminated soil samples was also examined through calcium source utilization ability in the biological processes of growth and nutrition. Results have revealed that the presence and biodiversity of Rhizopus sp were significantly higher than the genus of Aspergillus in the order of (Rhizopus, Penicillium, Fusarium, and Aspergillus) respectively. The high growth rates of the Fusarium sp isolates on soil samples contaminated with CaO indicate the possibility of using these fungi in the bioremediation of soil contaminated with cement as a cheap and eco-friendly technology.